Preparation of colored metallo-alpha-oximino ketone complex images



Patented Dec. 5, 1950 PREPARATIQN F EOLORED .hiE'iA'LLfla.-

QMMINO' KETONE COB 1P1]EXv WAGES Donald E. Sargent, Easton, Pa,assignor'to General Aniline &. Film Corporation, New York,

'Y.., .a corpnration hi Delaware No Drawing. Application July 8, 1949,Serial No. 103,757

2 Glaims.

The present invention relates to photographic elements containingcolored IIlBtflllO-w-OXilllillO ketone complex images, and to a methodof preparing such images.

One of the most commonly used methods for forming colored photographicimages involves developing an exposed silver halide emulsion with aprimary aromatic amino developer in the presence of a color former suchas a phenol or a compound containing a reactive methylene group. 'Theoxidation products of the "developer react with the color former toproduce a colored dye image. Such images suffer from the disadvantagethat they arenot particularly light-fast. It is known thatcc-OXi-Ifli-HO-kGtOHGS having a structure:

C.OH

LNG

are capa-oleof reacting with certain metallic ions such .as ferrous ionsto yield highly colored products. When an iron .salt capable of yieldingferrous ions is used, chelate compounds usually green, blue-greener bluein color and presumably of the following structure:

tic/J1 are formed. a-oximino-ketones have found use as reagents fordetecting ferrous iron, and the ferrous iron complexes thereof have, incertain cases, been used as dyestufis for textiles 'see Color Index Nos.1 to 6).

'I have now discovered that these colored metallo-a-oXimino-ketonecomplexes may be formed in situ Witha silver halide image by treating aphotographic element bearing a silver halide image with a compoundcapable of reacti'ng with said silver halide to form a less solublesilver compound and capable of yielding an ornitroso-ketone' structureupon nitrosation, nitrosating the silver compound formed by suchtreatment with aqueous nitrous acid and converting the resultant highlyinsoluble ni-trosated silver salt to a colored metal complex. Where aniron salt is employed for such conversion, a cyan ferrousoz-OXilIllllO-kBtOl'lE complex of exceedingly high fastness to light isproduced.

The images produced in this fashion and the preparation of the sameconstitute the purposes and objects of the present invention.

The compounds'which I utilize in my procedure form --insoiublenitrosatable silver salts by virtue of the fact that they contain athioamide grouping which is capable of isomerizing to an isothioamidegrouping and contain a nitrosatable methylene group adjacent to a ketogroup or a structure capable of isomerizing thereto.

Compounds Within the above category which I have found to beparticularly suitable for such use are Z-thio'barbituric acid and thel-aryl-, 1- alkyl, l-ara1kyl-, or l-alkylenederivatives thereof, such as1-phenyl-2-thiobarbituric acid, 1 (a naphthyl) 2 thiobarbituric acid,1-(5- naphthyl) -2thiobarbituric acid, 1-.toluy1-2--thi0- barbituricacid, 1-methylQ-thioharbituric .acid, leethyl-r2-thiobarbituric acid,1---pro-pyl-2-thio harbituric acid, l-buty-l-Z-thiobarbituric acid, 1-o.ctyl-.2-thiobarbituric acid, l-decyl-Z-thi-obarbituric acid,l-dedecyl-Zthiobarbituric acid, 1-- blenzyl- 2 th-ioharbituric acid,l-(I-methyl-Z- naphthyl)-2--thiob-arbituric acid,1-all-yl-2-thiobarbituric acid, .l-isopropenyl-2-thioloarbituric acidand thioureas substituted on one nitrogen atom by-a .hydroxy-naphthylgroup such as 5 thioureido-lmaphthol, S-thioureidolqnaphthol, '7thioureido-Z-naphthol, G-thioureido-l-naphthol.

The above thioureido naphthols are included I salt forming conditions toisomerize tothe isothioamide grouping:

and for the further reason that the wand naphthols have the knownability to yield aoXimino-ketone structures upon nitrosation.

All -of. the above compounds exhibit solubility aqueous alkalinesolutions, i. e., of sodium 3 turate. The white areas of the element,since they contain no silver halide, are unaffected by this treatmentand upon subsequent washing the excess of the sodium Z-thiObarbiturateis removed from these areas. The silver Z-thiobarbiturate image is thennitrosated by bathing the element in aqueous nitrous acid, after whichthe element is washed to remove excess nitrous acid. The nitrosatedimage is finally converted to a metal complex image by bathing theelement in a solution of a water soluble metal salt, preferably aferrous salt. In this way the silver halide image is replaced by anintensely colored metallo-a-oximino-ketone complex image which is cyanin color when ferrous iron is used as above.

The method involved may be more readily understood by a consideration ofthe following equations which indicate the reactions involved in formingthe complex image:

it? ii AgX Na-SC CH2 AgS(|J CH2 +HONO HNC=O BIN-(3:0

Silver Na Z-thiobarbiturate Ag Z-thiobarbit- Nitrous halide urate imageacid image AgS N HN C=O II I Fe++ AgSC C=NOH HNC=O o c I Fe N--O 4n Ag5-oximino-2-thio- Ferrous barbiturate image salt Cyan ferrous ironcomplex image wherein X=halogen and n=2 or 3.

It is to be understood that these equations are merely indicative of mytheory of the reaction and is not to be construed as the exact mechanismby which the complex images are produced.

In the nitrosation step, it is preferable to use a bath containing asmall amount of sodium nitrite dissolved in a weak organic acid such asacetic acid, formic acid, and the like. Excellent results have beenobtained when employing a 1-3 solution of sodium nitrite dissolved in2-5% of acetic acid.

The metal salts which may be employed for producing the final image areany Water soluble ferrous or cobaltous salts, such as ferrous sulfate,ferrous nitrate, ferrous acetate, ferrous chloride, cobaltous sulfate,cobaltous acetate. cobaltous chloride, and the like. Where a cobaltoussalt is used for forming the metal complex, the resulting image isorange in color rather than cyan.

The invention is further illustrated by the following examples, it beingunderstood that the invention is not restricted thereto.

Example I A film carrying a silver bromide image was treated for 1minute with a 0.5% solution of Z-thiobarbituric acid in 5% sodiumcarbonate at 18 C. and then washed to remove the 2-thiobarbituric acidfrom the white areas. The silver Z-thiobarbiturate image was nitrosatedby treatment with a 1% solution of sodium nitrite dissolved in 2% aceticacid for 2 minutes at 18 C. After washing for 3 minutes in running waterat 4 18 C., the film was treated in a 1 solution of ferrous sulfate for2 minutes. After washing again for 3 minutes, the film was cleared ofunconverted silver bromide by treatment in an acid hypo bath.

The above process produced an excellent duplicate in cyan color of theoriginal silver bromide image. This image was found to be extremelylight-stable, practically no fading occurring in hours in a Fade-ometer.Many cyan dyes used in color photography fade badly in 5-10 hours.

Example II The procedure is the same as in Example I excepting that theZ-thiobarbituric acid is replaced by an equivalent amount of1(a-naphthyl) -2- thiobarbituric acid. The image formed was cyan incolor and possessed a light fastness comparable to that of Example I.

Example III The procedure is the same as in Example I excepting that the2-thiobarhituric acid is replaced by an equivalent amount of5-thioureidol-naphthol. A green image of high light stability is formed.I

ErampZe IV The procedure is the same as in Example I excepting that theferrous sulfate is replaced by an equivalentamount of cobaltous acetate.There is produced a bright orange image which is eX- tremely fast tolight.

Various modifications of the invention will occur to persons skilled inthis art, and I therefore do not intend to be limited in the patentgranted except as necessitated by the appended claims.

I claim:

1. The proce s of producing ci-OXllTllllO-kllODG complex images in aphotographic element which comprises treating a silver halide image insuch element with an aqueous alkaline solution of a compound capable offorming silver salts less soluble than silver halides and containing athioamide grouping capable of isomerizing to an isothioamide groupingand a structure yielding rr-eximino-ketone compounds upon nitrosationand selected from the class consisting of a-ketomethylene and 1- andZ-hydroxy naphthalene structures, nitrosating the resulting silver saltwith aqueous nitric acid and treating such silver salt with a solublemetal salt selected from the class consisting of soluble ferrous andcobaltous salts to convert the nitrosated silver salt image into anintensely colored metalloc-oximinolretone complex image in situ with theoriginal silver halide image.

2. The process of producing a ferrous a-OXimino-ketone complex imagefast to light in a photographic element which comprises treating asilver halide image in such element with an aqueous alkaline solution of2-thiobarbituric acid to form a silver Z-thiobarbiturate image,nitrosating the resulting image with aqueous nitrous acid and treatingthe resulting nitrosated silver salt image with a water soluble ferroussalt to form a cyan ferrous iron a-oXimino-ketone complex image in situwith the original silver halide image.

DONALD E. SARGENT.

No references cited.

1. THE PROCESS OF PRODUCING A-OXIMINO-KETONE COMPLEX IMAGES IN A PHOTOGRAPHIC ELEMENT WHICH COMPRISES TREATING A SILVER HALIDE IMAGE IN SUCH ELEMENT WITH AN AQUEOUS ALKALINE SOLUTION OF A COMPOUND CAPABLE OF FORMING SILVER SLATS LESS SOLUBLE THAN SILVER HALIDES AND CONTAINING A THIO AMIDE GROUPING CAPABLE OF ISOMERIZING TO AN ISOTHIOAMIDE GROUPING AND A STRUCTURE YIELDING A-OXIMINO-KETONE COMPOUNDS UPON NITROSATION AND SELECTED FROM THE CLASS CONSISTING OF A-KETOMETHYLENE AND 1- AND 2-HYDROXY NAPHTHALENE STRUCTURES, NITROSATING THE RESULTING SILVER SALT WITH AQUEOUS NITRIC ACID AND TREATING SUCH SILVER SALT WITH A SOLUBLE METAL SALT SELECTED FROM THE CLASS CONSISTING OF SOLUBLE FERROUS AND COBALTOUS SALTS TO CONVERT THE NITROSATED SILVER SALT IMAGE INTO AN INTENSELY COLORED METALLO-A-OXIMINOKETONE COMPLEX IMAGE IN SITU WITH THE ORIGINAL SILVER HALIDE IMAGE. 